The invention relates to a process for the manufacture of adapted, fluidic surfaces.
Gas turbine blades, in particular those for aircraft engines, as a rule, are made as forged elements, in which case the gas turbine blades are provided with machining allowances in the region of their flow inlet edge as well as their flow outlet edge. If such gas turbine blades are to be used, for example, in the manufacture of an integrally bladed rotor, a so-called Blisk (Bladed Disk) or Bling (Bladed Ring), the gas turbine blades must be machined in the region of the flow inlet edge and flow outlet edge, before the blades are mounted to the rotor, in order to provide adapted, fluidic surfaces in the region of the flow inlet edge as well as the flow outlet edge.
Referring to prior art, the gas turbine blades are machined in order to manufacture adapted, fluidic surfaces in the region of the flow inlet edge as well as the flow outlet edge in that the gas turbine blades are milled in order to remove excess material and are subsequently manually round to ensure fluidic surfaces in the region of the flow inlet edge as well as the flow outlet edge. Manual rounding is time-consuming, expensive and cannot be reproduced. A manual rounding of gas turbine blades to provide adapted, fluidic surfaces in the region of the flow inlet edge as well as the flow outlet edge, therefore, represents an overall disadvantage.
German Patent Document DE 199 22 012 C1 relates to a process for the manufacture of adapted fluidic surfaces on integrally bladed rotors. The process described there is used after the gas turbine blades have been manually rounded in the region of their flow inlet edges as well as their flow outlet edges and joined to the rotor in a material-closed manner. The process in accordance with DE 199 22 012 C1 is used for machining gas turbine blades joined to the rotor in the region of the blade pans, i.e., in the region of a suction side, as well the pressure side thereof. However, this process is not used to manufacture fluidic surfaces in the region of the flow inlet edge and the flow outlet edge of gas turbine blades before the gas turbine blades are joined to a rotor in a material-closed manner.
Based on this, the object of the present invention is to provide a novel process for the manufacture of adapted, fluidic surfaces.
This object is achieved by means of a process for the manufacture of adapted, fluidic surfaces. In accordance with the invention, the process comprises at least the following steps: (a) generating a nominal milling program for the manufacture of fluidic surfaces in the region of one flow inlet edge and/or one flow outlet edge for an ideal gas turbine blade; (b) measuring the area of an actual gas turbine blade in the region of one flow inlet edge and/or one flow outlet edge thereof; (c) generating a milling program adapted to the actual gas turbine blade in order to manufacture fluidic surfaces in the region of the flow inlet edge and/or the flow outlet edge for the actual gas turbine blade, whereby measured values determined in step (b) are used to adapt or change the nominal milling program generated in step (a) to the milling program for the actual gas turbine blade; (d) manufacturing of the fluidic surfaces on the actual gas turbine blades in the region of the flow inlet edge and/or the flow outlet edge by milling with the use of the milling program generated in step (c), whereby, in a first partial step, coarse-milling, in particular roughing, is used to remove material in the region of the flow inlet edge and/or the flow outlet edge, and whereby, in an adjoining second partial step, fine-milling, in particular planing, is used to automatically round the flow inlet edge and/or the flow outlet edge.
Within the meaning of the present invention, a process is suggested with which gas turbine blades can be fully automatically machined in the region of their flow inlet edges as well as their flow outlet edges. Within the meaning of the present invention, the removal of material in the region of the flow inlet edge and flow outlet edge, as well as the rounding of the edges, is performed fully automatically by milling, so that the manual rounding required by prior art can be omitted. Consequently, time and costs for the manufacture of fluidic surfaces on gas turbine blades can be significantly reduced. Furthermore, reproducible manufacturing outcomes can be achieved.
In accordance with an advantageous development of the invention, the actual gas turbine blade is measured in such a manner that, in the region of the flow inlet edge and/or in the region of the flow outlet edge, respectively one series of measuring points is determined on a suction side and on a pressure side of the gas turbine blade, whereby each of these four series of measuring points consists of several measuring points distributed over the height and/or length of the flow inlet edge and/or the flow outlet edge. The series of measuring points determined on the suction side is used to change the nominal milling paths affecting the flow inlet edge and the flow outlet edge in the region of the suction side in such a manner that each nominal path point of these nominal milling paths having a corresponding measuring point is shifted by the value of deviation between the ideal gas turbine blade and the actual gas turbine blade in the region of the suction side. An interpolation is performed for the nominal path points of this nominal milling path for which such points no corresponding measuring point is available. The procedure is analogous for the pressure side. Likewise, an interpolation is performed for the nominal milling paths located between the nominal milling paths of the suction side and the nominal milling paths of the pressure side in order to adapt the paths to the actual gas turbine blade.